This invention relates to a semiconductor device of a laminated construction.
In most cases, the silicon oxide has been used as the interlaid insulating film of the three dimensional integrated circuits as disclosed in Extended Abstract of 2nd Workshop on Future Electron Device--SOI Technology and 3D Integration--[FED SOI/3D Workshop], March 19-21, 1985, pp. 19-23 "Laser Recrytallization on Multi-Layered Structure". An example of using silicon nitride and phosphosilicate glass (PSG) as an insulating layer is described in a paper entitled "Three Dimentional CMOS IC's Fabricated by Using Beam recrystallization" IEEE, Electron Device Letters, Vol. EDL-4, No. 10, Oct. 1983. A SOI (Silicon On Insulator) technique utilizing the solid phase epitaxy of amorphous Si is disclosed in a paper entitled "Amorphous Si/crystalline--Si facet formation during Si solid phase epitaxy near Si/SiO.sub.2 boundary", J. Applied Physics, 56 (12), 15 July 1984, pp 279-285. The SOI by zone melting technique is described in a paper entitled "Dislocations and twins formed in zone melted recrystallized Si on SiO.sub.2, " J. Applied Physics, 56 (8), 15 Oct. 1984, pp. 2213-2217.
One example of the semiconductor element having the laminated construction in the prior art is illustrated in FIG. 1. As shown, a SiO.sub.2 layer 8 having a thickness of 1.about.1.5 microns is formed on a silicon substrate 7 by the sputtering technique and then a silicon active layer 9 is deposited on the SiO.sub.2 layer 8.
The SiO.sub.2 layer 8 utilized in the element having the conventional laminated construction has a linear thermal expansion coefficient of 0.35.times.10.sup.-6 deg.sup.-1. Although definite values of the linear thermal expansion coefficients of the PSG, BSG and PBSG are not yet confirmed, it is estimated that these values are considerably smaller than the linear thermal expansion coefficient 2.5.times.10.sup.-6 deg..sup.-1 the silicon forming the active layer 9.
According to the presently used SOI technique, an amorphous silicon or a polycrystalline silicon deposited on an insulator is heated to grow crystal particles from solid phase or liquid phase, or a silicon is directly deposited on a heated insulator. When any one of these methods is used to form the element of a laminated construction, there is a large difference between the temperature for forming the laminated construction (especially the temperature for forming the silicon active layer), and the operating temperature (usually room temperature) of the element.
This temperature difference and the fact that the thermal expansion of the interlayer insulating film is smaller than that of the silicon active layer cause a residual stress not only in the silicon active layer but also in the interlayer insulating film at the operating temperature of the element. In an extreme case, microcracks are formed.